Modern supermarkets require a large amount of refrigeration for freezing and chilling the goods purchased by its customers. Typically, the freezers and coolers are located in random positions about the customer areas of the supermarket, in optimum locations for marketing purposes. In some instances, large closed refrigerated spaces and fixtures, including walk-in freezers or walk-in coolers are provided for butchers and other personnel of the supermarket, and occasionally for customers where large stocks of chilled items are maintained. While these larger closed refrigerated spaces are highly desirable, it is also desirable to use as little refrigerant coolant fluid as possible to chill these spaces. This is because the refrigerants must pass through an evaporator in the chilled space and there is a hazard that the refrigerant will leak into the atmosphere of the closed chilled space and be inhaled by customers, workers, and others. Refrigerants may replace oxygen in a closed space and result in oxygen deprivation, and possibly death by asphyxiation.
As a result of this hazard, federal and state regulations limit the amount of refrigerant that can be used to cool freezer rooms and other large closed refrigerated spaces which can be occupied by a person, either by an employee of the supermarket or by a customer. In most instances, the typical walk-in refrigerated space, etc. requires more refrigerant than is permitted by the federal and local regulations in order to adequately cool the space, particularly when people frequently move into and out of the chilled space. The result of this situation is that walk-in refrigerated spaces and other large closed refrigerated spaces that have frequent entry of people and therefore a large refrigeration load are not commonly available in typical supermarkets.
Thus, it can be seen that it would be desirable to have available to supermarkets and other businesses a large closed refrigerated space that can be adequately chilled for its intended purposes without requiring a volume of refrigerant fluid that is in excess of the standards set by federal and state regulatory bodies to directly communicate with the evaporator in the refrigerated space.